A470 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1911. 
numbers being from 20 to 30 feet high; the usual shape of the trunk 
was cylindrical, although many showed a conical form at the enlarged 
base. Among North American species the largest known is Cyathea 
Brunei, as it occurs on the lower slopes of the Volcano Turrialba in 
Costa Rica. The trunk of this is nearly cylindrical and very stout, 
12 to 15 feet high, 12 to 20 inches in diameter, and clothed with the 
dead hanging fronds of previous seasons; the fronds measure 12 to 15 
feet long and 5 to 6 feet broad—truly a giant among ferns. 
It is interesting to note, however, that in addition to the two very 
small American species previously mentioned a fair number of Cya- 
theacez have failed to develop a pronounced upright habit, and that 
several of these are among the largest-fronded species of the family; 
for instance, Alsophila quadripinnata (A. pruinata) and several species 
of Hemitelia, section Cnemidaria. The former, which in one state or 
another ranges through the West Indies and from Mexico to Chile, 
has enormous fronds, 9 to 15 feet long, borne in a spreading crown 
from a short erect stem which is rarely more than 3 feet high and 
usually much less, averaging perhaps 1 foot high, with a diameter of 
3 to 5 inches. Jenman has called attention to the fact that the stem 
of this commonly ‘‘ buds and throws up from the base a number of 
minor stems about half the size of the primary one,” a condition 
which is comparable to the development of the fasciculate or multi- 
cipital crown in the male fern (Dryopteris filiz-mas) and other common 
northern species, but which is not found in many Cyatheacee. The 
Cnemidaria species mentioned show a wide amount of variation in 
length of trunk. One or two South American members of this small 
and exceedingly interesting section have tall slender trunks, but most 
of the North American representatives have the stem either short (1 
to 3 feet high), thick, and erect, as in Hemitelia (Cnemidaria) horrida 
(pl. 11), or a little longer, and weakly ascending, rarely attaining the ° 
dignity of a trunk. 
TYPES OF UPRIGHT TRUNKS. 
Two main types of upright trunks may be distinguished readily 
among the American Cyatheacex: The first, in which the fronds, like 
those of Cyathea arborea, fall completely from the trunk in old age, 
leaving clean-cut scars; a second type, in which the fronds are imper- 
fectly jointed to the trunk and thus are slowly deciduous, commonly 
hanging for several years after dying, and even when fallen leaving 
parts of their bases as a rough outer covering to the trunk. More 
species have trunks of the first sort than of the second; but the latter 
condition is not at all uncommon, and is apparently the rule for species 
of Dicksonia. It is common also to many species of Cyathea, among 
which may be mentioned C. nigrescens in Jamaica and C. araneosa in 
Cuba. Some species are intermediate in this respect; and many (e.g., 
